Perimeter



May 1, 1945- w. FEINBLOOM PERIMETER Filed Dec. 24, 1942 2 Sheets-Sheet 1 \m w mm M. mw I s Q KN \N N a WILLIAM EINBLOOM, INVENTOR.

Arm/win May 1, 1945. w. FEINBLOOM PERIMETER Filed Dec. 24, 1942 2 Sheets-Sheet 2 WILLIAM FEINBLOOMJIQVVENTOR.

. efficient operation.

Patented May 1, 1945 cm-T D] 's-rms i 'r PERIMETERH imam N w-t rtar; I '1 Apnlicat'ion Decem er 24, 1942;Seriztlhlo; 470 I I A e m 1.8s;g f f This invention relates to perimeters, devices for testing and determining the angle'of vision and the location cf'blind spots in the human eye.

It is an objector this invention to' provide a tion and accurate in its results. t Another. object of' this invention is to provid a perimeter in which the person undergoing the test personally actuates the recording'mecha msm.

One of the features of my device is ,i'ts' sim plicityof constructio'nf Another feature resides in the positive record ing mechanism which allows the person being tested no chance for after thoughtspreconsiderations or rationalizations.

portable perimeter that is both simple in opera- Still another feature. of ,the' invention resides inthat a. dark-room is not necessary .for its Other and further objects andffeatures will become apparent from the following specification and the accompanying drawings in; which like numerals of reference indicate identical parts, 1

andinwhichz' r I Fig. l is a cross-section through the perimeter as a whole; Fig. 2 is anend view of the perimeter, taken along. line 2 10f Fig. 1, showing the control knob and the. recording chart; F 3; is

a section of the control knob, taken along line 3-4 of Figs. 1 and. 2;;and Fig. 4: is a schematic diagram of the electric.circuitemployed. in. the

perimeter.

In the drawings. a horizontal hollow terminating. atone end, in the substantially semispherical. bowl 2 and in the wide flange lat the other end. The tube l is welded-centrally to-tube I and-the latter screws into base 5 on which the complete mechanism is supported.

Rotatively supported within tube l, as it extends into bowl 2 and out through flange 3,is tube 6. The end of tube 6 within bowl 2 is open. Across this open end, pivoted on pin 1, is positioned mirror 8. Pin 1 is supported in the walls of tube 6. Intermediate one side of the mirror 7 knob I3 tube 6 is rotated. Fastened to rod II,

and positioned within a recess in the back of knob 13; lie'sspurfge'air l'lli 'l'his gear meshes with 'the'rack l5 slldably supported in the T-slot [6 in knob l3 (Fig.3). Riveted to an extreme enclof the rack isthe'flatspring-metal strip' 11 which terminates at its; free end in the stylus I8. Attached to a substantialportion of the mid section of spring I'Ti'sj'thiron armature'ra Rotation ofkjiob i3 rotatstiibdfi, mirror 8; and stylus l'8 with "respect to tube I." Rotation ofk'nob f2' extends or retracts'thest'ylu's and simultaneously tilts the mirror'B-Xjvith"respect to theia x is oftubel'. Within tube 6, casting itsj'light through aperture 29 and lens 2f onto mi'n'or' 8,is"light-bulb '40. The lens and" aperture are so. chosen that a comparatively sharpspot of light-is focused from f the bulb onto the inner surface of bowl 2. Also within tube B,arrang'ed'in operable relation tojthe armature I9, is pesitione'd the electric ma BQtfZZ One. lead oftheelectric current to both, the bulb and t the magnet is grounded;. the ther Ie ds B 4. We .QQnflfiQl re e vely to the insulated slip-rings lia'nd .26 en l the] out .side of tube 6.. By means of. the wipers fl, leads 23 and '24 are continued by lead's zs' and itv to the relayj28. relay is, actuated. by. the pushbutton 29 positioned without the instrument b t connectedthereto bythe fle gible'electric cord 30. e The-electric circuit employed, is shown in. Fig.

4. ,Current I is. derived froma standard source through plug v 31, wires 32,.ahd transformer' 33.

'..The relay 28-is astandardcommercial one; available von the market today, wherein the armature closes. one circuit and opens another on being .attracted by. the electi e-magnet. The-relayis equipped with a manual reset so that once the first circuit is opened, knob 34 of cam 3 ',;must be manipulated to close that circuit again. Knob 34 is shown in Figure l, cam 34' is shown'in the diagram, Figure 4,

With the relay in the normal orreset position the current is on in the light circuit. When button 29 is depressed, the relay opens thelight circuit and closes the electro-magnet circuit; whereupon said electro magnet 22 draws armature [9, together with stylus, l8, toward itself. With this movement the stylus will make a mark' on the graph paper 35 held by clips 36 tothe face Bulb 40 can not light again until Hole 38 isframed with wire and is supported by a wire spider 39 from the edge of bowl 2. The spokes of the spider are so arranged that when a person places his eye at hole 38 the spokes will not interfere with the protruding features of the face such as the nose, chin and brow. The elastic sheet 3], on the other hand will yield to permit such protrusion; the eye, however, will be kept at hole 38 in fixed predetermined relation to the bowl.

The use of the above perimeter is simple, Chart 35 is so calibrated and so inter-related "to the extensions of the stylus l8 and the tilting of mirror 8 that the angle A, the angle included between the axis of the instrument and the line from the center of aperture 38 to the'spot of light reflected from the mirror onto the inner surface of the bowl, will be indicated by the stylus on' said chart for any setting of the instrument. ,The patient has one eye blind-folded and places his other eye against aperture 38. stylus l8 indicates the meridian for which the eye is to be tested. Then knob l2 isrotated so -that then tilted slowly to bring th spot of reflected light gradually from the rim of the bowl 2 to- Knob I3 is rotated until the mirror is tilted to reflectlight on the back of sheet 31.- Then the bulb 40 is lit. The mirror iswards its center. When the patient first becomes aware of the light spot he is supposed to press the button 29. As he doesso, the light immediately I goes out and the stylus'records the angle of p61- ception. The operations-may be repeated for as manymeridians as desired. v, g,

The patient cannot waver too lon to express his judgment, nor can be retract his impulse once he has pressed the button to make the permanent record. In order to avoid distraction and to help him focus his eyes forward, a small section 4| of the back of the mirror .has its silvering removed to allow a pin-point of light from bulb 40 to shine directly into the patients eye. If it is desired to testfor color sensitivity, diaphragm 23 may be replaced by a color filter. In order to make the instrument more portable, transformer 33 may be replaced'by dry batteries. The transformer is used because it is felt not desirableto use high voltage current in a device of this sort.

From the 'foregoing description it will be seen that I have devised a simple, inexpensive and enicient machine to accomplish the objects set forth. While I have described the simplest elements be resorted to without departing from the spirit .or sacrificing any of the principles of the invention.

bowl.

light spot on said inner surface.

What I claim is:

1. A perimeter comprising a substantially semispherical bowl, a diaphragm across th face of the bowl having an aperture adapted to accommodate the eye to be tested, a mirror positioned within the bowl, a light source directed to the mirror, and means to vary the angular position of the mirror in any meridian with respect to the bowl so that light can be reflected by the mirror on to any portion of the interior surface of the 2. A perimeter comprising a substantially semispherical bowl, a diaphragm across the face of the bowl having an aperture adapted to accommodate the eye to be tested, a mirror positioned within the bowl, a light source positioned behind the bowl, means directing the light rays from the light source to the mirror through. an aperture in the bowl, and means to vary the angular position of the mirror in any meridian with respect to the bowl so that light can be reflected by the mirror to anyportion of the interior surface of the bowl.

3. Adevicesubstantially, as described in claim 1 -Whe1'Bin-the means which varies the angular position of the mirror is linkedand synchronized with indicating means without the bowl to' indicate the angular position of the mirror with-1mspect to the bowl. I V V r I 4. .A perimeter comprising a substantially semispherical bowl, mean to position the eye at a predetermined position at, the face of the bowl, a rotatable tube in axial alignmentwith the bowl, one end of the tube positioned within thefbowl at the rear thereof through an aperture. therein,

a mirrorpivotally mountedat sai 'endof the tube, a light source mounted within the tube,

means todirect light from the. source to themin ror, and means to tilt the mirror on its pivotal mounting so that the light rays may be reflected positioned within the bowl at the rear thereof through an aperture therein, a light {source mounted within the tube,'me ans to project a light spot from said sourceonto the inner surface'of the bowl, and means to vary the position of the WILLIAMFEINBLOOM. 

